Mold for casting clay articles



B. W. WHITE.

MOLD Fon cAsTmG CLAY ARTICLES.'

APPLICATION FILED M lG.24. |920.

mm1 May 9, 1922.

FIBJ.

/NVENTOR @M '771 M55,

ffl-*f iii ROBERT w. WHITE, or nrwoon, INDIANA, as'srGNoR To PITTSBURGH PLATE Grass COMPANY, .a CORPORATION Vor, PENNSYLVANIA.

MOLD rca CasTINe 'CLAY ARTICLES.

Leraars.

To all 107mm t may concern.'

` Be it known that l, ROBERT 7. WHITE, a citizen of the United States, anda resident lof Elwood, in the county of Madison and r`l casting clay articles such as tank blocks,

iioaters, pots, tuilles and the like. It has 'for its primary objects, the provision of a mold for the purpose specified which, (l) is cheaper than the plaster f molds heretofore used, (2) requires less skill to construct than the plaster molds, permits the 'reuse oi" the material employed, and (a) is subject to less breakage than the plaster molds.

`When clay is cast in shapes such as those speciierhthe walls of the molds must be constructed 'of material adapted to take up the excess moisture in the clay and promote the setting of the clay. Plaster of Paris has been used with some success for this purpose in connection with small articles, but is objectionable for a number of reasons and parmv ticularly so in connection with the formation of relatively large articles. One objection is the difficulty involved in utilizing the plaster after the mold is cracked or broken, as the'used plaster is almost worthf less and forms an accumulation which is oftenl a source of expense `to dispose ot. Further the'making of plaster molds is a trade so that skilled and expensive labor is required. As the size of the mold is increased its weight tends to cause increased breakage in handling as the plaster is relatively fragile and the expense is greatly increased due to the great thickness in the walls required in order to secure the necessary strength. The weight due to the thick walls also makes the labor` of handling the mold in assembling and disassembling very heavy.

The present invention is designed to overcome the objectionable features of the yplaster mold by substituting a mold having a supporting structure of wood, iron, or other similar relatively strong material with a lining of plaster board or other material having a capacity for absorbing moisture corresponding to that of plaster. Such a mold may be made of ample strength for producing poured or cast articles of the Specification of Letters Patent.

Applicationiled August 24, 1920. Serial No. 405,709.

rammed May 9, 1922.

largestsizeisuch as pots or tuilles, and the f.

lining of p'lasterboard can be removed and dried. andV used over again many times. Molds -of `this vcharacter are not subjectV to breakageto any extent and may be con-- structed by relatively unskilled labor. They are also much lighter and more easily handled.

Certain embodiments of the invention are i illustrated in the accompanying drawings, wherein Figure l is a plan view of a mold constructed in accordance with the invention and designed `l-'or casting tank blocks. Fig. 2 isa section through the mold of F ig. l on the linen- 11, and Fig. gis a horizontal sec tion taken through a portion of the wall of a pot mold embodying the invention.

Figs. l and 2 illustrate a knock-down mold containing the improved construction and designedV for the productionv of tank blocks.

- This mold comprises the base plate l and the side plates 2, 3, Il, and', preferably of wood.

The side plates 3 rand 5 are clamped in'position by means of the transverse bolts 6 pro vided with suitable nuts, the plates 2 and e being held by the clamping action of the bolts and by reason .of the engagement of their outer faces with the bolts asindicated in Fig-.2.4

A lining of plaster board in the form of the sheets 7, 8, 9, 10, and ll is provided upon the interior of the mold. The material used for this purpose is preferably commercial plaster board about one-quarter inch thick, although the thickness of the plaster board and its composition may be varied to suit conditions.

One form or plaster board which has been cfound to meet the requirements satisfactorily is made in accordance with the `following formula lli/'ood fiber `Waste paper Sulphite 2,500 pounds Lime 500 Cement 2,000 Stucco 22,000

The sulphite of the formula is a paper pulp such as is formed in the production of paper, wherein the materials are heated in a digester in connection with sulphuric acid. rlhis material is not essential but makes the mass stick together better. The stucco of the formula is plaster of Paris and the cement is ordinary Portland cement. This plaster board is one which is upon. the market and is in'the form of sheets Which are relatively porous and much lighter and stronger than plaster of Paris` andv at the same time has a capacity for absorbing moisture to substantially the same extent as plaster of Paris.

The plaster board is preferably merely set in position inside the mold, although it' desired it maybe tacked in position, after which theclay is poured in the mold inthe;

usual Way and allowed to set. The setting of `the clay requires from twenty-four to forty-eiglit hours, after. Which the plates 2, 3, a, and 5 with the plaster board lining is removed, leavingthe clay article upon the sheet 7 carried bythe plate 1. The final drying operation' requires several Weeks,

:afterivhich the block is ready for arching in the usual Way.

After their removal the plaster board sheets are allowed to dry out and canbe then used again. The plaster board is rela- Itively strong and durable and may be used over and `over again, so that the expense incidenty to the use of plaster is reduced to a minimum. vlf desired, metal plates'may be used as the supporting structure, although Wood is preferable and the streng-th and `lightness of the material makes it possible to v'cast articles of large size `such as the tuilles, pots,.a`iid 'iloaters heretofore referred to. ln the case of largeiarticles a thicker 'plaster board may be vemployed in order to give greater absorbing capacity, or several thicknesses of plaster board may be used. A number of diliierent kinds of commercial kplaster yboards may be employed, although Ythe one specified heretofore is preferred.`

lvNhenit is desired to produce anarticle with a circular Wall, such asa pot, theeX- pedient illustrated in Fig.A 3 may be employed in order to avoid the necessity of ,bending the plaster board. As here illusl trated, the mold Wall is made in the Jform of panels, the boards l2 constituting the supporting 'framework and the sheets 13 being of plaster board. This forms a supporting wall Which is sufficiently near to cir cular form to meet requirements and which does not require any bending of the materials employed. rllhe `material may be readily adaptedto a large number of dif` .ferent forms, it being a relatively simple matter to construct a mold of the desiredy shape out of Wood and cut the plaster boardv sheets to forma lining. The cost of the materials employed is much less than inthe case of solid plaster Walls, and'there is practically no breakage or cracking incident to handling, such as is the case with molds tively strong material liavingon their facesslieets or' plaster board, such board comprising mixture of plaster-of-Paris and Wood ibre.` I i 3,. ln combination in a mold for casting clay articles, walls comprising knock-down plates each having upon its `inner side a sheet of commercial plaster boardmade up oi' plaster-oi-Paris vand Wood libre. y

ln testimony whereof, I have hereunto subscribed my name this 5th day of August,

iioianrrr WL WHITE.

Witnessz BRoccARD F. BRANDLEss.

rlhe mold is also Vso 

